The object of the proposed research is to conduct an extensive search for a new material which would be suitable for prolonged use as a soft denture liner. The specific goals of the project will be: 1) to examine by both physical and biological methods the materials which are commercially available as soft denture liners and determine their various shortcomings; 2) to test other commercial liners; 3) to synthesize and test new materials as candidate soft liners; 4) to optimize the best candidate materials with regard to mechanical and biological acceptability and processibility; and 5) to prepare the materials for clinical evaluation.